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·R01 GrantA Research Project Grant awarded by the National Cancer Institute. This type of grant provides support for a specific research project initiated by an investigator in the field.

·RAResearch Assistant; Research Associate.

·radiation oncologistA physician who specializes in the use of radioactive substances and x-rays for the treatment of tumors and cancer.

·radiation therapistA health professional who gives radiation therapy as part of a team led by a radiation oncologist.

·radiation therapyThe use of radiation energy to interfere with tumor growth. Also called irradiation.

·radicalRadical surgery is the resection of a tumor and a wide margin around the tumor in an attempt to remove any spreading cells.

·radioactiveGiving off radiation.

·radioactive monoclonal antibodiesAn antibody is a substance produced by white blood cells in response to a foreign object (an antigen). The human body often considers tumor cells to be foreign objects because they have unique proteins (antigens) Because an antibody binds only to a specific antigen, it can act as a homing device to a tumor cell. Monoclonal antibodies, manufactured in large quantity in the laboratory, can be mated to radioactive isotopes which kill tumor cells.

·radioisotopeAn unstable element that releases radiation as it breaks down. It can be used in imaging tests or as a treatment for cancer. Also called isotope.

·radiolabeledAny material that has been joined to a radioactive substance.

·radiologistA physician trained in the use of , x-rays, and other imaging techniques to arrive at a diagnosis.

·radionuclide scanningA technique to produce images of internal parts of the body. A small amount of radioactive material is injected or swallowed. A scanning machine then measures the radioactivity in certain organs.

·radioprotectorsDrugs used to protect normal brain cells from the effects of radiation therapy.

·radioresistantResistant to radiation therapy.

·radiosensitiveResponsive to radiation therapy.

·radiosensitizersDrugs used before or during radiation therapy to make tumor cells more sensitive or vulnerable to radiation therapy.

·radiosurgeryStereotactic radiosurgery. A special, focal form of radiation therapy that uses a large number of narrow, precisely aimed, high dose beams of ionizing radiation. The beams are aimed from many directions circling the head to meet at the tumor. The treatment is delivered in one session. Stereotactic radiotherapy or fractionated stereotactic radiosurgery (FSRS) is stereotactic radiosurgery delivered in multiple fractions over a period of time. Stereotactic radiosurgery is commonly abbreviated SRS.

·RAIDRapid Access to Intervention Development. A program of the National Cancer Institute (NCI) to facilitate translation to the clinic of novel, scientifically meritorious therapies originating in the academic community.

·randomized studyA study having two or more “arms.” The treatment arm (standard versus new) assigned to each patient is determined by a computer. Randomization is used to prevent bias and ensure that an equal number of patients are assigned to each arm of the study.

·rateA measure of the amount of a disease in a specific population, calculated by counting the number of patients with the disease and dividing by the total population at risk. Rates are expressed as a unit of person-years (usually 100,000). A person-year is one person for one year.

·rCBV [r c b v]Acronym for regional Cerebral Blood Volume, a measure of the flow of oxygenated blood through the brain.

·RCTRandomized Clinical Trial.

·RDRegistered Dietician.

·real time MRIThis technique produces MRI images in a faster sequence than traditional MRIs. The increased speed permits the visualization of the use of oxygen by the tumor and the brain tissue. This technique is important because it depicts an area of the brain “lighting up” when the patient performs a task, such as moving a finger, or speaking. In this way, brain maps of functional areas are generated, useful for preoperative surgical planning and intraoperative avoidance of functional or “eloquent” areas of the brain. Also called echoplanar, functional, or Fast MRI.

·receptor-mediated permeabilizersA way of delivering drugs through the blood brain barrier. Receptor-mediated permeabilizers are synthetic substances modeled after naturally occurring compounds. These substances temporarily increase the openings of the blood brain barrier, allowing drugs to pass into the brain. Abbreviated RMP.

·RECISTResponse Evaluation Criteria in Solid Tumors. A set of rules that defines when tumors shrink (respond), stay the same (stable), or grow (progress) during treatment. Clinical trials investigating new treatments often use RECIST to evaluate response to treatment. The basic criteria (simplified) are:

oComplete Response (CR): Disappearance of a tumor(s)

oPartial Response (PR): At least a 30% decrease in the diameter of a tumor

oProgressive Disease (PD): At least a 20% increase in the diameter of a tumor

oStable Disease (SD): Neither PR nor PD

·recurrenceReappearance of the tumor. The return of symptoms or the tumor itself, at the same site as the original (primary) tumor or in another location, after the tumor had disappeared for a time.

·red blood cellsCells that carry oxygen to all parts of the body. Also called erythrocytes or RBCs.

·registered nurseA trained professional who assists people with their healthcare under the direction of a physician. Abbreviated RN.

·rehabilitationThe process of restoring mental and/or physical function after illness or injury, often with the assistance of specialized healthcare professionals.

·relapseThe return of signs and symptoms of a disease after a period of improvement.

·remissionThe disappearance of symptoms or the disappearance of the tumor. A remission can be permanent or temporary.

·resection[ree sek´ shun] Surgical removal of a tumor. Often used with an adjective, for example, macroscopic total resection — removal of all visible tumor; partial or subtotal resection — some visible tumor could not be removed.

·reservoirsA small “container” such as an Ommaya Reservoir is surgically placed under the scalp. A tube leads from the eservoir into a ventricle of the brain. Medications are injected via syringe into the reservoir and then the reservoir is pumped. The pumping begins the flow of drug through the ventricles and lining of the spine. Chemotherapy administered this way is usually repeated on a regular schedule.

·residentA medical doctor who has completed medical school and internship, and is receiving further training in a specialized area. Completion of a residency program is required for board certification in a medical or surgical specialty.

·residual tumor[ree zid´ yu al]Tumor remaining after reatment.

·respirationBreathing. To inhale and exhale.

·reticular formation[reh tik´ you lar]A network of nerves in the center of the brain stem.

·retinoidVitamin A or a vitamin A-like compound.

·RFARequest for Applications.

·RFPRequest for Proposals.

·risk/benefit ratioThe relationship between possible risks and potential benefits of a treatment. Patients and their families must decide if the ratio is reasonable for them.

·risk factorAnything that increases the chance of developing a disease.

·Ribonucleic AcidOne of the two nucleic acids found in all cells. The other is DNA. RNA transfers genetic information from DNA to proteins produced by the cell. RNA directs the manufacture (synthesis) of proteins.

·RNRegistered Nurse.

·RNARibonucleic Acid.

·robotic surgery[row bot´ ik]An experimental system consisting of a computer, microscope and mechanical arms to hold instruments that assists surgeons when performing delicate and prolonged surgeries.

·ROMRange of motion.

·RPARecursive Partitioning Analysis. A statistical method of identifying patient subgroups with significantly different survival rates. A tool used to improve the design of clinical trials.